THE FLORA OF MISSISSIPPI. 141 



Along low, wet spring branches thickets of alder {Alnus 

 serrulata) and willow {Salix nigra) grow in dense masses. 



The bottoms of the Tennessee, Tombigbee and Tus- 

 cumbia rivers and their larger branches, support remnants 

 of what was once a heavy growth of white, willow and water 

 oaks (Quercus alba, Q. phellos, 0. aquaticus), basket oak 

 {Q. Michauxii), sycamore {Platanus occidentalis) , beech 

 (Fagus ferruginea) , river maple {Acer dasycarpum) , black 

 gum (Nyssa multiflora), red gum (Liquidamber styraci- 

 flua), and cypress {Taxodium distichum). In addition to 

 these, in the higher grounds in the valleys are black locust 

 {Robinia pseudacacia), hackberry {Celtis Mississippiensis), 

 ash {Fraxinus Americanus), sassafras {sassafras officinale), 

 box elder ( Negundo aceroides) , red bud ( Cercis Canadensis) , 

 and hop horn-bean {Ostrya Virginica). Not infrequently 

 among these will be found growing the great-leaved mag- 

 nolia {Magnolia macrophylla) , which is common in the 

 state south of the Vicksburg and Meridian railroad, but 

 rare in the northern parts of the state. The paw paw 

 {Asimina triloba) and silver bell {Halesia tetraptera) are 

 rather common shrubs on the river bottom lands. 



Eleven species of this region have not yet been found 

 elsewhere in Mississippi. These are as follows: 



Pinus inops, Heuchera villosa, 



Epigaea re pens, Dentaria multifida, 



Chimaphila maculata, Cardamine Pennsylvanica, 



Viola pubescens. Iris cristata, 



Hepatica triloba, Houstonia coerulea. 

 Hepatica acutiloba, 



Species that have been found on Pontotoc Ridge and 

 one or two adjoining counties to the west, as well as in 

 the region under consideration, are the following: 



Camptosorus rhizophyllus , Corylus Americana, 



Asplenium angustifolium, Juglans cinerea, 



Saxifraga Virginiensis, Heuchera Americana. 

 Anemonella thalictroides , 



